Air Trek North

Multi Engine Add-OnGround Material

Definitions• • VR – Rotation speed. The speed at which back pressure is

applied to rotate the airplane to a takeoff attitude.• • VLOF – Lift-off speed. The speed at which the airplane

leaves the surface. (Note: some manufacturers reference takeoff performance data to VR, others to VLOF.)

• • VX – Best angle of climb speed. The speed at which the airplane will gain the greatest altitude for a given distance of forward travel.

• • VXSE – Best angle-of-climb speed with one engine inoperative.

• • VY – Best rate of climb speed. The speed at which the airplane will gain the most altitude for a given unit of time.

• • VYSE – Best rate-of-climb speed with one engine inoperative. Marked with a blue radial line on most airspeed indicators. Above the single-engine absolute ceiling, VYSE yields the minimum rate of sink.

• • VSSE – Safe, intentional one-engine-inoperative speed. Originally known as safe single-engine speed. It is the minimum speed to intentionally render the critical engine inoperative.

• • VMC – Minimum control speed with the critical engine inoperative. Marked with a red radial line on most airspeed indicators. The minimum speed at which directional control can be maintained under a very specific set of circumstances outlined in 14 CFR part 23, Airworthiness Standards. Under the small airplane certification regulations currently in effect, the flight test pilot must be able to (1) stop the turn that results when the critical engine is suddenly made inoperative within 20° of the original heading, using maximum rudder deflection and a maximum of 5° bank, and (2) thereafter, maintain straight flight with not more than a 5° bank. There is no requirement in this determination that the airplane be capable of climbing at this airspeed. VMC only addresses directional control. Further discussion of VMC as determined during airplane certification and demonstrated in pilot training follows in minimum control airspeed (VMC) demonstration. [Figure 12-1]

Propeller Basics• Featherable• Increased oil pressure

decreases pitch (High RPM)

• Loss of oil pressure puts propeller to full feather.

• A windmilling propeller at low pitch (high RPM) is like a disk, providing extremely high drag possibly making operation uncontrollable due to the high drag.

Propeller Basics• Full Feathering• Counterweighted• Oil Pressure to Decrease

Pitch• A constant Supply of Oil

Keeps the Propeller from Feathering

• Enables the Propeller to Feather if Oil Pressure is Lost or a Propeller Governor fails.

Propeller Hub

Propeller Basics

• What Drives to High Pitch (Low or Zero RPM)– Counterweights– Spring and Nitrogen

Charge– Lack of Oil Pressure

against the Spring and Nitrogen Charge

• What Drives to Low Pitch (high RPM)– Aerodynamic Forces

(wind)– Oil Pressure– Unfeathering Pins

Activate on Shutdown approximately 800RPM

Un-feathering Accumulators

• Stores a reserve of high pressure to give us a one shot push out of feather, then airspeed against the lower pitch prop starts a windmill to start the engine

• The high pressure oil is helped by a spring and nitrogen charge

• If fuel and ignition are present, the engine will start.

• High Oil Pressure from the Governor recharges the Accumulator just moments after engine rotation begins.

Combustion Heater

• It is a small furnace in the nose that burns fuel from the left tank.

• Provides heat to the cabin and defrost to the windshield.

• Automatic over-temperature protection is provided. Cannot be reset from the cabin.

• A cool down period is required.– Blower is utilized if cool down is conducted during

ground operations.

Accelerate-Stop Distanceis the runway length required to accelerate to a specified speed (either VR or VLOF, as specified by the manufacturer), experience an engine failure, and bring the airplane to a complete stop.

Accelerate-GO Distance

is the horizontal distance required to continue the takeoff and climb to 50 feet, assuming an engine failure at VR or VLOF, as specified by the manufacturer.

Climb Gradient• is a slope most frequently expressed in terms of altitude gain per

100 feet of horizontal distance, whereupon it is stated as a percentage. A 1.5 percent climb gradient is an altitude gain of one and one-half feet per 100 feet of horizontal travel.

• Climb gradient may also be expressed as a function of altitude gain per nautical mile, or as a ratio of the horizontal distance to the vertical distance (50:1, for example).

Service Ceiling

• All-engine service ceiling of multiengine airplanes – the highest altitude at which the airplane can maintain a

steady rate of climb of 100 f.p.m. with both engines operating.

• All-engine absolute ceiling– climb is no longer possible.

• Single-engine service ceiling – can no longer maintain a 50 f.p.m. rate of climb with one

engine inoperative.• Single-engine absolute ceiling

– climb is no longer possible.

Engine Failure After Lift Off• Regulations do not require that runway lengths be equal to or greater than acc-

stop distances.– For safety, this should be a min runway length.

• the option of continuing the takeoff probably does not exist unless the published single-engine rate-of-climb performance is at least 100 to 200 f.p.m.

Take Off and Climb Profile• Use 1000ft instead of 500ft for Cruise Climb

Profile Change for safety margin

Approach & Landing Profile• Full Stall Landings Should be Avoided.• Except for short field landings, land with a slight amount of power and pull

power to idle as mains touch the runway.

Short Field Take Off and Climb• Similar to Single Engine

– Power full with brakes on– Release brakes– Rotate at Vr– Climb at Vx until obstacle is clear, then Vy

Go Around• Be careful, gear retraction speed is 112kts.• Flaps should be retracted before the landing gear for two reasons.

– First, on most airplanes, full flaps produce more drag than the extended landing gear.

– Secondly, the airplane will tend to settle somewhat with flap retraction, and the landing gear should be down in the event of an inadvertent, momentary touchdown.

• A slight turn to offset the climb and parallel the runway is required so any traffic on the runway can be monitored

3 ScenariosEngine Failure after Lift-off

• Landing Gear Still DOWN– Close both throttles and land on the remaining runway or overrun

• Landing Gear Selector UP – Inadequate Climb Performance– When operating near or above the single-engine ceiling and an engine failure

is experienced shortly after lift-off, a landing must be accomplished on whatever essentially lies ahead.

– Remaining airborne, bleeding off airspeed in a futile attempt to maintain altitude is almost invariably fatal.

– Analysis of engine failures on takeoff reveals a very high success rate of off-airport engine inoperative landings when the airplane is landed under control. Analysis also reveals a very high fatality rate in stall-spin accidents when the pilot attempts flight beyond the performance capability of the airplane.

• Landing Gear Selector UP – Adequate Climb Performance– If the single-engine rate of climb is adequate, the procedures for continued

flight should be followed. There are four areas of concern: 1. control, 2. configuration, 3. climb, and 4. checklist.

Landing Gear DOWNEngine Failure after Lift-off

• Maintain directional Control• Land on remaining runway or overrun

Landing Gear UpInadequate Climb Performance

• When operating near or above the single-engine ceiling and an engine failure is experienced shortly after lift-off, a landing must be accomplished on whatever essentially lies ahead.

• Remaining airborne, bleeding off airspeed in a futile attempt to maintain altitude is almost invariably fatal.

• Analysis of engine failures on takeoff reveals a very high success rate of off-airport engine inoperative landings when the airplane is landed under control.

• Analysis also reveals a very high fatality rate in stall-spin accidents when the pilot attempts flight beyond the performance capability of the airplane.

Engine FailureConfiguration

The memory items from the “engine failure after takeoff” checklist [Figure 12-14] should be promptly executed to configure the airplane for climb. The specific procedures to follow will be found in the AFM/POH and checklist for the particular airplane. Most will direct the pilot to

The “identify” step is for the pilot to initially identify the failed engine. Confirmation on the engine gauges may or may not be possible, depending upon the failure mode. Identification should be primarily through the control inputs required to maintain straight flight, not the engine gauges. The “verify” step directs the pilot to retard the throttle of the engine thought to have failed. No change in performance when the suspected throttle is retarded is verification that the correct engine has been identified as failed. The corresponding propeller control should be brought fully aft to feather the engine.

1) Obtain VYSE, 2) SET takeoff power, 3) RETRACT the flaps and landing gear, 4) IDENTIFY the failed engine, 5) VERIFY the failed engine6) FEATHER the failed engine for least drag

Landing Gear UpAdequate Climb

Performance

Single Engine Climb

As soon as directional control is established and the airplane configured for climb, the bank angle should be reduced to that producing best climb performance. Without specific guidance for zero sideslip, a bank of 2° and one-third to one-half ball deflection on the slip/skid indicator is suggested. VYSE is maintained with pitch control. As turning flight reduces climb performance, climb should be made straight ahead, or with shallow turns to avoid obstacles, to an altitude of at least 400 feet AGL before attempting a return to the airport.

Engine Failure Checklist

Having accomplished the memory items from the “engine failure after takeoff” checklist, the printed copy should be reviewed as time permits.

The “securing failed engine” checklist [Figure 12-15] should then be accomplished. Unless the pilot suspects an engine fire, the remaining items should be accomplished deliberately and without undue haste.

Airplane control should never be sacrificed to execute the remaining checklists. The priority items have already been accomplished from memory.

Engine Failure during CruiseNot all engine failures or malfunctions are catastrophic in nature (catastrophic meaning a major mechanical failure that damages the engine and precludes further engine operation). Many cases of power loss are related to fuel starvation, where restoration of power may be made with the selection of another tank.

An orderly inventory of gauges and switches may reveal the problem. Carburetor heat or alternate air can be selected. The affected engine may run smoothly on just one magneto or at a lower power setting. Altering the mixture may help. If fuel vapor formation is suspected, fuel boost pump operation may be used to eliminate flow and pressure fluctuations.

Although it is a natural desire among pilots to save an ailing engine with a precautionary shutdown, the engine should be left running if there is any doubt as to needing it for further safe flight.

Engine FailureAbove Absolute Single Engine CeilingIf the airplane is above its single-engine absolute ceiling at the time of engine failure, it will slowly lose altitude. The pilot should maintain VYSE to minimize the rate of altitude loss. This “drift down” rate will be greatest immediately following the failure and will decrease as the single-engine ceiling is approached.

Due to performance variations caused by engine and propeller wear, turbulence, and pilot technique, the airplane may not maintain altitude even at its published single-engine ceiling. Any further rate of sink, however, would likely be modest.

Single Engine Approach and Landing

• Similar to Twin Engine Ops– Altitudes– Airspeeds– Key Positions

• Difference from Twin Engine Ops– Higher than normal power setting on remaining engine– Asymmetrical thrust– Landing gear extended at abeam point– Airspeed no slower than Vyse– Long, flat approaches are to be avoided– Final flap setting can be delayed until landing is assured– Once landing is assured, slow to 1.3Vso or per POH/AFM.

Don’t Do Single Engine Go AroundsSingle-engine go-arounds must be avoided. As a practical matter in single-engine approaches, once the airplane is on final approach with landing gear and flaps extended, it is committed to land. If not on the intended runway, then on another runway, a taxiway, or grassy infield.

The light-twin does not have the performance to climb on one engine with landing gear and flaps extended. Considerable altitude will be lost while maintaining VYSE and retracting landing gear and flaps. Losses of 500 feet or more are not unusual.

If the landing gear has been lowered with an alternate means of extension, retraction may not be possible, virtually negating any climb capability.

Engine Inop Flight Principles• Best single engine climb performance

achieved with– Vyse– Maximum Power– Minimum Drag

• Flaps up• Gear up• Inop engine propeller feathered• Minimum sideslip

• To achieve zero sideslip and max climb performance we use– Yaw of rudder– Horizontal component of lift from banking

1 of 2 Incorrect ScenariosOne Engine Inop

• Wings level• Large rudder force to keep ball

centered• Results in sideslip towards inop

engine• Vmc will be significantly higher

– This is how we will demonstrate Vmc in the air

• Climb performance is degraded

2nd of 2 Incorrect ScenariosOne Engine Inop

• Wings banked 8-10deg’s into operative engine

• No rudder force• Results in sideslip towards

operating engine• Large ball displacement• Vmc will be significantly higher • Climb performance is degraded

due to sideslip drag

Correct ScenariosOne Engine Inop

• Wings banked ~2deg’s into operative engine

• Rudder force to maintain directional control

• Results in zero sideslip• Small ball displacement of about ½ a

ball diameter• Vmc will be slightly higher than

published– Published Vmc was certified with a

maximum of 5deg of bank.• Results in maximum climb

performance

Three Major Accident Factors in OEI flight at low altitudes and airspeed• Pilots must be extra cautious of the following

during takeoff and landing– Loss of directional control– Loss of performance– Loss of airspeed

• Simulated loss of engine will NOT be performed during slow flight or stalls

Critical Inop Engine• Critical engine: The engine failure that has the most adverse effect on directional control• Conventional Twins

– Both props rotate clockwise as they do in a single– Critical engine failure will be the left engine due to P-factor

• Descending blade has more thrust than the ascending blade when under power and nose pitched up.• The descending blade of the right engine has a longer arm from the CG and so has more torque than the descending

blade of the left engine.• Thus, when the right engine is the operative engine, it has more asymmetrical thrust than an operative left engine (see fig

below)• Counter Rotating Props

– The BE-76 (Duchess) has counter rotating props• Left engine rotates clockwise• Right engine rotates counter-clockwise• Results in P-factor thrust to have minimum arm length from CG for both engines

– No critical engine is present since each engine’s thrust, due to P-factor, has the same arm from the CG

Conventional Twin

4 Factors Make Left Engine Critical• P-Factor

– Torque from right engine has a larger arm than torque from left engine since the greatest torque is on the descending blade

• Spiraling Slipstream– Spiraling slipstream does not hit the rudder from right engine, only left engine

• Accelerated Slipstream– Propwash provides more lift on the operating engine

• Torque– For every action, there is an equal and opposite reaction. If the right engine rotates clockwise,

then the the opposite reaction is to roll the engine/wing to left.

• http://media.avit.und.edu/f4_Inop%20Engine%20Trainer/f1_Inop%20Engine/060302/critical.html

• When losing the critical engine, both directional control and performance will suffer. In discussing directional control problems, the focus is on the concept of Vmc. In discussing performance, the focus is on the concept of Vyse. It is important to keep the two ideas separate to fully understand them.

Vmc was determined under the following conditions

1. Max power on operative engine– Provides for the most asymmetrical thrust

2. Windmilling propeller on inop engine– Provides for most asymmetrical drag due to the disc effect of a windmilling propellor

3. Most infavorable weight– As weight moves to max gross, Vmc decreases

4. Most infavorable CG– As CG moves aft, the rudder arm becomes shorter and the effectiveness of the rudder to maintain directional control. – Vmc decreases as CG moves forward.– Vmc increases as CG moves aft.

5. Landing gear retracted– Extended landing gear aids in directional control and decreases Vmc

6. Flaps and cowl flaps in takeoff position– Usually this is zero flaps and cowl flaps open.– Adding flaps increases symmetrical drag and thus Vmc decreases

7. Bank angle max of 5deg’s– VMC increases 3 kts for each deg of bank angle– 5deg’s is not zero sideslip and doesn’t give max climb performance

8. Sea Level – As altitude increases, the HP/weight ratio decreases and thus, asymmetrical thrust decreases which lowers Vmc

9. Maximum of 150lbs of rudder pressure– Increase in rudder pressure decreases Vmc

VMC vs Density Altitude• From the chart to the right, Vmc decreases as

density altitude increases– However, stalling speed (Vs) remains the same with

increasing altitude• We always want to do our Vmc demo’s while

remaining in the yellow– However, Vmc demo’s must be done to always be

3000ft AGL or greater per regulation.– BE-76 POH/AFM requires Vmc demo to be at least

5000ft AGL.• We never want to do our Vmc demo’s while in the

orange area– Recovery is difficult– This is basically a spin entry maneuver due to the

control inputs and entering a stall– Spins occur in this area of orange– Spin recovery in a twin is difficult if not impossible– Spin entry will be sudden with the plane going

inverted• How do we maintain safety at high altitudes

during Vmc demo’s?– We will use wings level instead of 5deg of bank to

ensure we loose directional control first before a spin (yellow area indicated by “yaw occurs first”)

No Solo Touch N Go’s

• There will be no solo Touch N Go’s• Touch N Go’s should not be considered until

the student has at least 15 landings in make and model and then, only with an instructor present.

• Touch N Go’s with an instructor should be done with– Student running the throttles and yoke– Instructor handling the flaps and trim

Other Publications• AC 61-84b Preflight• AC 91-13 Cold Weather Ops• AC 91-55 Reduction of

aircraft elec system failures during starting

• AC 90-42 Traffic advisories at airports without control towers

• AC 61-9B Pilot Transition Courses for complex single engine and light twin engine airplanes

• AC 90-66 Traffic patterns at airports without towers

• AC 150/5340-1 Stds for airport markings

• AC 150/5340/18 Stds for airport sign systems

• FAA-P-8740-19• FAA-S-8081-6C MEI PTS• FAA-S-8081-12C

Commercial PTS

Air Trek North

Multi Engine Add-OnGround Material